A photosensitive element in a general optical system is nothing more than a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). With the development of chip technology, a pixel dimension of the photosensitive element is constantly reducing, so that a camera lens carried on electronic products such as a mobile phone or a digital camera is developing to have high resolution, miniaturization and large field angle.
A general camera lens with the high resolution and large field angle needs a configuration of large aperture, such that requirements for illumination may be satisfied. However due to characteristics of large field angle and large relative aperture, the dimension often may be long, thus matching a high resolution photosensitive chip is difficult. It is mainly shown that a resolution power is not enough, a distortion is large and an angle of emergent of a chief ray is large.